Archive for Dairy Cattle Reproduction

Although I resolutely hate New Year’s Resolutions, I confess that each turning of the calendar year will find me dreaming up a “project” for the next twelve months. Although I hate resolutions because they just don’t work, nevertheless, I am hooked on projects that that actually do something! Thus, I happily substitute project planning for resolution breaking. However, the project chosen has to have certain features. It must make a difference. It must have a plan. It must have buy in, finances and scheduled action.

Today when I applied those criteria to topics for Bullvine articles, lo-and-behold in the cold dark days of January a light went on!!! Well duh! As I keep an eye on dear hubby’s daily trips to our little barn, I watch to see his progress by looking for the lights in various locations. Lights are also the handy way that my ninety-seven-year-old Mother in Love and I signal that “all’s well!” at her house next door! If the signal light is off after dark, it’s time for a check in. This led me to recall some experiments we implemented during our milking herd days regarding long-day versus short-day lighting on milk production and herd health management.

What’s Light Got to Do With It?

While it would seem simple to simply program dairy facility lighting to turn off and on for the desired amounts of time, there are other considerations that complicate the procedure. For one thing, not all dairy chores are on a predictable schedule. Calvings, maintenance, health issues all require that the human staff can see clearly to carry out their work. Happily, there are studies that allow the necessary dark time for the cattle but allow the necessary light for reading ear tags, medication or other detailed activities.

To measure the level of lighting available, a light measure should be used to measure the foot candles. Fifteen (15) foot candles of light in the housing is the recommended benchmark for benefiting from a long day photoperiod. At the other end of the light manipulation spectrum, darkness also plays an important role. Research shows that cows do not perceive light under five foot candles. This is an important piece of information, particularly for managing 3X operations and anywhere that employees need to be able to continue their work without disrupting the photoperiod being targeted for the herd. One recommended solution is the placing of low-intensity red lights 20 to 30 feet apart and 20 feet off the ground.

You might think the amount of light in your barn doesn’t matter much. Think again. You can improve cow comfort, herd health and productivity by the flick of a light switch.

Working in the Right Light

Studies carried out by Professor Alma Kennedy at the Universities in Canada (Manitoba and Alberta) conclude that dairy cattle can tolerate at least one foot-candle of white light and still experience this as “dark.” This research also showed that exposure to 5 foot-candles at night reduced the normal level of the main nighttime hormone (melatonin) by 50 to 70 percent, a significant interference with the animals’ normal nighttime function.

Based on the present research findings, it is determined that night light in dairy barns can be designed with an intensity of about 1 to 1.5 foot-candles. When this is the case, dim light at 1 to 1.5 foot-candles allows surprisingly precise observation. Literature reports that “a person with normal eyesight can read newsprint with one foot-candle of light. More specifically, dairy farmers report that ear tags can be read, and cows identified at a distance when using this level of dim light.” Some farmers refer to this as “moonlight.” Dual-level fixtures and specially designed fluorescent fixtures are commercially available to meet this purpose.

And the Studies Show…

Source: Dahl, G.E. & D. Petitclerc: Management of photoperiod in the dairy herd for improved production and health.

The investment in special lighting is well supported by research trials that provide proof on the effectiveness of long-day lighting as a tool for all dairy operations.

Lactating Cows – More production

There is up to a 10% increase in milk production when cows are given a long day photoperiod. One study reports that cows receiving 16 hours of light a day produce 3.7 pounds more milk a day than cows under a natural lighting scheme. Furthermore, after 20 days, the difference increases to 6.8 pounds per day. Sixteen hour lighting also slowed the decrease in milk production of those cows that originally started with natural lighting.

Lactating Cows – More DMI

Results of studies also supports that cattle exposed to long day lighting take in more dry matter. Compared to cows under a natural photoperiod of 9 to 12 hours of light, the 16-hour exposure can result in up to 6% more dry matter intake. It is interesting that the additional intake did not have a corresponding weight gain. This suggests that long day photoperiod cows are more feed efficient and are capable of converting increased dry matter intake into milk.

Photoperiod Can Affect Reproductive Performance

Dairy herds that provided 24 hours of light to cattle saw negative results. Providing 24 hours of light resulted in longer days between breedings, more days open, and more breedings per cow.

Numerous research studies in North America have clearly demonstrated that when dairy cows are provided summerlike, long days in the winter, they respond with increased milk production. The increase in yield noted in nine such studies average 5 pounds per cow per day. No adverse effects on fertility or health have been reported.

Light Can Mean Lower Age to Puberty

A goal of the industry has been to get heifers into the milking herd as soon as possible. Previous research has indicated that long day photoperiod can lead to leaner growth, greater mammary development, and lower the age to puberty by an average of one month. One study determined that breeding and calving of the heifers in the long day photoperiod occurred earlier than heifers in a short day photoperiod. Even though long day photoperiod heifers had a lower body weight, they did not experience limited skeletal growth. Instead, they had lower body condition scores because they were using the energy that they consumed for skeletal growth. Feed intakes did not differ between the short day photoperiod and long day photoperiod groups and long day photoperiod heifers spent less time at the feed bunk, which would suggest they were more feed efficient. The long day photoperiod heifers also had higher milk production throughout the first 5 DHI tests.

In one of the first studies looking at differences in the growth between heifers with supplemented lighting (16 hours) and natural lighting, heifers in the supplemented lighting group had a larger heart girth size of about 1.6 inches after the 16-week trial. These heifers also averaged 1.9 pounds of daily gain compared to the 1.7 pounds for the heifers in a natural lighting scheme.

Dry Cows Need Less Light

Dry cows have the opposite effect with a long day photoperiod compared to lactating cows and heifers. Providing dry cows with a short day photoperiod leads to higher milk production the next lactation. One study has shown milk production increased 6.8 pounds per day in the next lactation. Milk, fat and protein yields were also higher in the short-day photoperiod cows. A short-day photoperiod also lead to 2.9 lbs more daily dry matter intake during the dry period.

Additional Management Factors

Farmers have many different protocols to increase milk production including manipulating the amount of light available throughout the day. One practice that would yield significant results would be to start managing lighting at a young age. Producers should provide long day photoperiod to their heifers to help increase dry matter intake and make them more feed efficient. Providing a long day photoperiod would also allow them to breed heifers at an earlier age. Dry cows benefit the most from a short day photoperiod, 8 hours of light and 16 hours of dark. Dry matter intake increases when dry cows have shorter lighting periods.

With ever-narrower margins, dairy farmers are always seeking tools that will improve the productivity of their dairy farms.

First make the plan. Modernize and develop lighting on your dairy enterprise.

Then consider the finances. Sure there will be expenses but there will also be proven profitability.

The Bullvine Bottom Line

As we have learned, long-day light is a simple and well-proven technique to increase milk production and profitability.

Don’t make resolutions that you won’t follow through on.

Instead, make sure that you’re seeing your dairy herd in the right light!

It matters not whether you are breeding or implanting heifers or cows in your herd; the question is are they cycling and are their uteruses in the state that they can receive a fertilized egg and establish a pregnancy. It’s big bucks off the bottom line if your females are not cycling when they should. It means carrying more animals than necessary, extra feed costs, extra labour, semen and embryos down the drain. We all know that the number one reason for culling is reproductive failure. It all comes down to being proactive rather than reactive when managing for reproductive success.

On Being Prepared

I was reminded of how important this is when I visited a very successful 200 cow dairy on a hot (90F) and steamy (80% humidity) day in August of last year. I was impressed to see that the cows were producing, on average, 5.7 pounds of fat plus protein per day. What really drew their reproduction program to my attention was when the owners showed me a fifth lactation cow that was almost eight years old. She was producing 120 pounds of 4.0% fat and 3.5% protein milk having calved 83 days previously and at that moment she was in standing heat.

The purpose for my visit was to study the equipment the herd was using to monitor the health and reproduction in their herd (Read more: Better Decision Making by Using Technology and Robotic Milking: More than just automation it’s a new style of herd management.). My take away from that visit was that it takes being prepared for both the cows and heifers to be ready and able to get pregnant. Furthermore, the heifers in the herd were starting to be bred a 12 months of age and on average were calving at 22 months. They were breeding their heifers by weight. As the owners told me their success story, they were not stressed about getting animals in calf although they were looking for information so they could do an even better job on their reproduction program.

Beyond the Feed

Every nutritionist, worth their salt, carefully considers and advises dairymen on how to best feed their animals from birth to herd removal in order to achieve reproductive success. Semen handling, insemination and implantation techniques and sire, cow and heifer conception rates are topics that vets, reproduction specialists and semen sale people advise owners and staff on. Moreover, now geneticists are producing genetic indexes for fertility, pregnancy rate and body condition scores. And the staff working on the reproduction in herds are continually being trained on how to achieve success.

But it goes further than that in order, as Sue Brown of Lylehaven Holsteins (Read more: LYLEHAVEN: Developing the Dream) told us, for the vet to report the great news “She’s Pregnant”.

The Britt Theory

In 1992, Dr. Jack Britt, well know and very respected veterinarian from North Carolina State, published an article entitled Impacts of Early Postpartum Metabolism on Follicular Development and Fertility. Don’t let the title frighten you. This paper comes from a vet that grew up with dairy cows, judged cows in college, conducted research and educated students at Michigan State, NC State and U of Tennessee and has spoken extensively to breeder groups about reproduction in dairy cattle.

In short, Dr. Britt brought to the attention of all of us that the follicles that are available for ovulation, at the time of heat, were produced 60 – 80 days before a heat. The state of the female’s health and wellbeing when the follicle started to be formed is very important. Dr. Britt’s paper reported that “If follicles are exposed to adverse conditions such as severe negative energy balance, heat stress or postpartum disease during the initial stages of growth, this could affect gene expression, resulting in impaired or altered development. Such an impairment could result in the formation of dysfunctional mature follicles, which produce poor oocytes and result in the formation of weakened corpora lutes”. In other words, poor follicles won’t develop properly, and the resulting egg will not conceive. End of story.

Although Dr. Britt’s paper was published over twenty years ago, all breeders should ask themselves if it has relevance for their dairy operation.

Britt Theory Supported

Numerous other researchers have supported Dr. Britt. Their work includes more detailed study of the effect of NEB (Net Energy Balance) on embryo development, stressed cows and follicular development, follicular development and the ET donor, environmental factors that disrupt oocyte function and much more.

Beyond the Cow Herd

It does not start and stop with the milking cows. Heifer breeding in a herd likely makes up 25% of the breedings on a farm. Having healthy, well grown heifers able to conceive at 12 months of age takes both a plan and follow through action.

The Bullvine Bottom Line

Conception will not just happen. Drugs alone won’t solve the problem. As breeders, we need to dig deeper and truly know what goes on in our herds reproductively. Success takes having a plan. Success takes a team approach – vet, nutritionist, technician, repro specialist, owner and staff. Are you ready?

If you were to describe the perfect program to achieve top female fertility in your herd, what would it be? Would your program include heifers calving at 22 months of age and every 11-13 months thereafter until lifetime production reaches 275,000 lbs (125,000 kgs) of milk? For decades breeders have heard that they can’t breed for fertility. It’s all management and nutrition. Well that story is changing. Let’s examine how genetics can play a role in improved fertility in a herd.

The Current Scenario

The CDCB (Council on Dairy Cattle Breeding) has summarized the following current reproduction information on the current US dairy cattle.

Holstein cows take 2.5 breedings per conception. Jerseys take 2.2.

Holstein cows average 80 days in milk before they are bred. Jerseys average 77 days.

Average calving interval for Holstein cows that calve back is 13.8 months. Jerseys average 13.0 months.

Average conception rate for Holstein cows is 32%. Jerseys average 41%.

Average age at first calving in Holsteins is 26 months. Jerseys average 23.5 months.

These stats for Holsteins and Jerseys are provided for breeders to benchmark their herds, not to start a breed war. In five years’ time even if a Holstein herd was able to achieve the current Jersey average it will not be good enough. The three biggest factors that stand out from these stats and that are in need of correction are: 1) days to first breeding; 2) number of breedings before conception; and 3) age at first calving.

As it turns out the reproductive performance of North American dairy cows and herds reached their lowest level in 2007 and since then there has been minor genetic improvement.

Source: CDN – March 2010 – A Look at Fertility from Two perspective

Breeders Must Address Fertility

An attitude shift is needed. We must move from tolerance of fertility to awareness that genetics plays a role. Not all breeders have accepted the need for change. The Bullvine analysed the sires with the most progeny registered with Holstein US over the past two weeks and found that nine, yes nine, of the top twenty had negative genetic ratings for Daughter Pregnancy Rate (DPR). In fact two sires had significant negative ratings of -2.5 and -3.5. In addition four of the twenty had only slightly positive ratings. In total 13 of the top 20 sires were not breed improvers for DPR. That is significant!

Some breeders have paid attention to the management side of fertility and have increased their pregnancy rate by aggressive heat detection, by using professional A.I. reproduction specialists (Read more: Artificial Insemination – Is Doing It Yourself Really Saving You Money?) by installing heat detection devices or by using hormone level monitors (Read more: Better Decision Making by Using Technology). However from the latest reports from milk recording, half the herds have a pregnancy percent of less than 15%. And only 10% of herds have a pregnancy rate of 21% or more. Clearly more attention needs to be paid to getting cows and heifers pregnant.

Genetic Tools to Aid with Fertility

Daughter Pregnancy Rate (USA) and Daughter Fertility (Canada) are the primary genetic evaluation ratings to use when selecting for improved female fertility. These indexes are created using data from insemination, milk recording and type classification.

However there are eleven other genetic ratings that have some influence on reproduction. Individually they may not be significant but collectively they can contribute to reproductive problems or solutions.

Persistency – high lactation yielding cows that have flatter lactation curves put less strain on their bodies

Inbreeding – inbreeding negatively affects reproduction

Haplotypes – information is now coming available to show that certain haploids hinder reproduction

Semen Conception Rate – although not a genetic rating, low fertility semen should be avoided

Those are the tools available today. We can expect that, with the current research into genomics and reproduction, there will be new ratings to assist with breeding more reproductively sound animals in the future.

Selection Matters

The Bullvine recommends that after breeders short list the sires they intend to use that they eliminate sires that do not have a DPR over 1.0 or a DF over 103. Yes, female fertility is included in TPI, NM$ and LPI but the emphasis on fertility in these total merit indexes is not high enough to result in major genetic improvement for fertility. The following lists of bulls are examples of bulls that significantly improve total merit as well as female fertility.

Table 1 Top Ranking US Sires by Daughter Pregnancy Rate

Table 2 Top Ranking CDN Sires by Daughter Fertility

Action Plan

It is important for both herd viability and sustainability that the following steps be followed.

Do not use bulls that are genetically inferior for reproductive traits.

Use herd management software and herd protocols to assist with reproductive management.

Ensure that animal housing and animal grouping result in healthy animals

Feed cows and heifers according to their performance and reproductive needs

Employ staff training and education program for reproduction.

The Bullvine Bottom Line

The genetic attention starting to be given to female reproduction on dairy farms is long overdue. The first step for breeders is to include reproduction in your herd genetic improvement plan (Read more: What’s the plan?). In as little as five years, by following a progressive proactive plan, breeders will significantly reduce their losses due to reproduction.